The ambassadors also reached a preliminary agreement on broadening the legal basis of the Russia sanctions.

One EU diplomat told EUobserver that both the status and the number of the new Russian names mooted in the ambassadors’ meeting were “small and disappointing”.

The contact added the two firms are Crimean energy companies confiscated from Ukraine after Russia annexed the territory in March, but they are so minor that “very few people, even among the experts, had heard of them”.

The previous legal basis of the sanctions says the EU can target people who are “responsible” for events in Ukraine and “entities … associated with" the individuals.

The new legal basis is said to broaden the terms to include people and firms who also “benefitted” from the transfer of Crimean assets.

“It’s a bit better. But it still doesn’t let the EU go after the really important persons in Moscow,” the EU diplomat noted.

A second EU source said: “We are still at the level of what we call ‘stage two’ sanctions, designations of individuals, not ‘stage three’, designations of whole sectors of the Russian economy.”

The sanctions debate comes despite the fact Russian leader Vladimir Putin said on Wednesday he has withdrawn troops from the Ukrainian border and called on separatists in Donetsk to put off a referendum on independence.

But the rebels rejected Putin’s appeal and aim to hold the vote on Sunday as planned.

When asked by press in Washington on Thursday if the US has evidence the Russian troops have moved, state department spokeswoman Jen Psaki said: “We have not … No.”

She added: “It’s more than just comments we need. We need actions. We still continue to believe the Russian government has an ability to influence what the separatists are doing on the ground, so we’ll look to see if that happens over the coming days.”

A third EU source noted the new sanctions are not tied to the referendum only.

“We also have the 9 May military parades in Moscow and in Crimea [which Putin plans to attend], so we’ll be looking at the messages coming out of this. Events are evolving and we have to see what happens on the ground … It’s going to be a long weekend."

The diplomat’s comments highlighted the difference between EU hawks and doves on Russia.

Former Iron Curtain states, Nordic countries and the UK are keen to target senior Russian interests on the US model. But Cyprus, France, Germany, Greece, Italy, and Spain are more wary.

Asked by this website if the new names and entities are “disappointing”, the third EU diplomat said: “We’ve already listed 48 people and some of them are very high-ranking. We need to implement sanctions gradually and progressively because they are not designed to punish people, they are designed to bring the other side onto the de-escalation path.”

The latest plan to calm the crisis is a “Road Map” put forward by Switzerland in its role as the chair-in-office of the OSCE, a Vienna-based multilateral body.

It includes holding an OSCE-moderated “round table” between Kiev authorities and rebels and has already won favour in Kiev.

Meanwhile, the US and France on Thursday indicated that relations with the Kremlin have not broken down despite the rhetoric on both sides.

The White House said Putin should come to France on 6 June to celebrate the anniversary of D-Day with President Barack Obama and European leaders. “We would not expect France to dis-invite Russia from this historic event commemorating World War II because of what's taking place in Ukraine … Millions of Russian lives were lost in the war against Nazi Germany,” a US spokeswoman, Caitlin Hayden, said.

A French government source told Reuters that France is still planning to deliver the first of two advanced “Mistral” naval vessels to Russia in the fourth quarter of this year as part of a €1.2 billion deal dating before the crisis.

The second ship, named the Sevastopol after the Crimean port which hosts Russia’s Black Sea Fleet, is to be delivered in 2016.

“Our position remains the same. No decision [on blocking the delivery] before October,” the French source said.